Color management products allow the creation of device characterization profiles for various input or output devices, such as printers. These profiles, such as ICC (International Color Consortium) compliant profiles, allow for proper color handling across many types of devices in digital workflow of computer images. For example, in order to create a printer profile, the printer creates a sheet of color patches arranged in a predetermined pattern. A spectrophotometer then scans the color patches. The absolute measurements made by the spectrophotometer comprise a set of data that characterizes the producible color gamut of the printing device, ink, and media combination; From this data set, a profile for the device is created. The device profile then may be used to insure uniform color display.
Recently, hand-held spectrophotometers have been developed for use in color management. The hand-held spectrophotometers are in many ways easier and more convenient to use than larger spectrophotometers. However, current hand-held spectrophotometers do have certain disadvantages.
In order to accurately, robustly, and rapidly measure a group of color patches, the movement over the color patches by the spectrophotometer must be associated with the individual color readings. A mechanical linear feedback mechanism such as a wheel is placed in contact with the color patches. As the spectrophotometer is moved, the wheel measures the speed and direction of such movement. Because the wheel is contact with the color patches, the wheel may distort the color patches, making the measurement by the spectrophotometer inaccurate. Additionally, the wheel, due to use or malfunction, may inaccurately measure the distance, and thereby causing faulty readings of the color patches resulting in re-scanning or a poor quality device profile.
Second, the hand-held spectrophotometer may be allowed to contact the sheet of color patches during the scan. The contact by the hand-held spectrophotometer may alter the visual appearance as well as the absolute color where the contact occurs, and thus result in inaccurate readings and a poor quality device profile. An example of such a device is the “EyeOne”, manufactured by Gretag-Macbeth AG.
Third, the hand-held spectrophotometer must be tethered to a computer, usually by a serial or USB (Universal Serial Bus) cable. The information gathered by the spectrophotometer is sent to the computer by way of the USB cable. Thus, the length of the USB cable restricts the area where the spectrophotometer may be used. This is inconvenient, especially if the device being measured by the spectrophotometer is not located near the computer. Insufficient work surface around computer workstations, to adequately scan over a printed target without cord binding or scan influence and interference, also leads to inaccurate readings and a poor quality device profile.
An improved color measurement system that provides for more accurate color readings and can be used away from the computer is thus highly desirable.